Satellites or moons are celestial bodies that orbit planets or dwarf planets. They do not emit their own light either. Asteroids are rocky bodies, smaller than planets, which orbit a star. Comets are masses of ice, dust and rock that move around a star in a very long elliptical orbit. As comets get closer to a star, the ice they contain changes into gas. This gas is illuminated by the light from the star and forms a tail behind the comet. Meteoroids are solid bodies that come from asteroids, comets or other matter in the Universe. When a meteoroid enters the Earth’s atmosphere, it usually burns up and disintegrates, becoming a meteor, also called a shooting star. The pieces which reach and hit the Earth’s surface are called meteorites.